The present invention relates to a needle for a sewing machine; more particularly, to a needle allowing visual observation of insertion in a clamping device, not susceptible of faulty installation in a clamping device, and of a clamping device therefor.
Conventional needles for use in household sewing machines are produced with a reference flat in a butt end for orientation during insertion and fastening to the needle bar of the sewing machine. The needle is inserted blindly, coaxially with the axis of the needle bar into a clamping device comprising a multiplicity of components such as a clamp body, an orienting gib, and a fastening screw. Economy clamping sets do not contain a gib to aid in sewing needle orientation. Thus, in economy clamping sets it is normally possible to insert a needle in the wrong orientation, causing sewing difficulties due to improper location of the thread grooves in the needle and/or of the needle eye with respect to the loop taker. In clamping devices with a gib, proper orientation is assured by the flat, but initially inserting the needle can be frustrating because there is a 50% chance of presenting the needle shank out of the required alignment on the first trial. Needle insertion, in any event, is accomplished blindly because of the need to load the needle axially with the needle driving bar. The necessity for a clamping torque on the fastening screw provides another source of problems in that needles too loosely clamped may damage the sewing machine or harm the operator, whereas needles too tightly clamped to avoid the bad effects of loose clamping may present difficulties during removal.
What is required is a sewing needle design and clamping system therefore, which permits a sewing machine operator to visually obtain correct loading of the sewing needle, and proper clamping thereof, without the difficulties encountered, and the multiplicity of fine parts required, with the prior art constructions.